Astaxanthin is classified as a xanthophyll, which is a carotenoid pigment, and can be found in microalgae, yeast, salmon, trout, krill, shrimp, crayfish, crustaceans, and the feathers of some birds. Haematococcus pluvialis , a green microalga and one of the richest sources of natural astaxanthin, was reviewed and cleared for marketing by the United States Food and Drug Administration (FDA) in August 1999 as a new dietary ingredient by means of the Dietary Supplement Health and Education Act (DSHEA) (21 CRF part 190.6). Astaxanthin is most commonly used as an antioxidant and may be beneficial in decreasing the risks of certain chronic diseases, such as cancer and cardiovascular diseases. Astaxanthin may also be effective in carpal tunnel syndrome, rheumatoid arthritis, muscle strength and endurance, high cholesterol (LDL oxidation), musculoskeletal injuries, and male infertility. Astaxanthin has been used as a feed supplement and food coloring additive for salmon, crabs, shrimp, chickens, and egg production. According to the Code of Federal Regulations, astaxanthin is generally recognized as safe (GRAS) when used as a color additive in salmon foods to obtain the desired pink to orange-red color.